build: switch to stable qrules and ampform

[redeboer]

In addition, extract pytest configuration to pytest.ini and define testpaths there. Since b9b72ed, it is become impossible to run tests through VSCode. Defining testpaths fixes this. In addition, it removes the last 'non-tox' section from the tox.ini file (see 7eb3866)

[codecov]

Codecov Report

Merging #265 (b802d1c) into main (5fde3be) will increase coverage by 84.19%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           main     #265       +/-   ##
=========================================
+ Coverage      0   84.19%   +84.19%     
=========================================
  Files         0       13       +13     
  Lines         0      753      +753     
=========================================
+ Hits          0      634      +634     
- Misses        0      119      +119     

Flag	Coverage Δ
unittests	84.19% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/tensorwaves/optimizer/minuit.py	93.22% <0.00%> (ø)
src/tensorwaves/physics.py	78.26% <0.00%> (ø)
src/tensorwaves/interfaces.py	82.14% <0.00%> (ø)
src/tensorwaves/optimizer/_parameter.py	100.00% <0.00%> (ø)
src/tensorwaves/__init__.py	100.00% <0.00%> (ø)
src/tensorwaves/optimizer/__init__.py	71.42% <0.00%> (ø)
src/tensorwaves/data/__init__.py	96.77% <0.00%> (ø)
src/tensorwaves/data/transform.py	100.00% <0.00%> (ø)
src/tensorwaves/optimizer/callbacks.py	74.72% <0.00%> (ø)
src/tensorwaves/model.py	83.33% <0.00%> (ø)
... and 3 more